Field of the Invention
The invention relates to a method for a quick power regulation of a power station system. The power station system has a turbo-generator set with a steam turbine and a generator. Energy storage mechanisms, which are present in the system process, are activated. The generator power is increased as a result. The invention further relates to a device carrying out the method for a quick power regulation.
In addition to compensating frequency deviations within a power supply system, it is particularly important to keep a prescribed interchange power at coupling points to subnetworks. These subnetworks make up a distribution network which may be an interconnected network or a separate network. An important requirement is therefore that a quick power increase of a power unit is available within seconds.
The printed publication "VGB Kraftwerkstechnik" (VGB Technology of Power Stations), Issue 1, January 1980, pages 18 to 23 suggests methods for a quick power regulation and a frequency back-up control. While a plurality of intervention possibilities may be carried out simultaneously or alternatively for a quick power regulation in the range of seconds (seconds reserve), a lasting change in the power of a power unit requires a change in the fuel supply. In order to bridge delay times in a fossil-fired power station system, throttled steam turbine governing valves can be opened within seconds. This activates available steam or energy storage mechanisms and utilizes them virtually without delay.
In addition to a power increase by canceling the throttling of governing valves of the steam turbine, preheaters may also be shut down. These preheaters are provided in the water-steam cycle of the steam turbine and are heated with extraction steam from the steam turbine. A condensate flow in the low-pressure heater may be stopped and increased again within a few seconds. The above-described measure for a quick power regulation in fossil-fired power units by shutting down the preheaters with a condensate stop as a further possibility for activating energy storage mechanisms held in reserve is also described, for example, in the German Patent DE 33 04 292 C2.
It is therefore customary to use a regulating device in order to regulate and/or control the so-called quick seconds reserve. The quick seconds reserve refers to a regulated utilization of steam flows to regenerative preheaters and/or heating condensers as well as a utilization of the process steam and of the condensate in the water-steam cycle of the steam turbine of a power station system. For a quick power regulation, that is to say for an activation of the energy storage mechanisms within seconds, the regulating device throttles the steam supply to preheaters, throttles the process steam and/or throttles of the condensate. Desired setting values for regulating valves at turbine extraction points and for actuators setting the condensate are determined such that a required extra generator power is achieved. A disadvantage is that the coordination of the positioning elements or actuators at the turbine extraction points and of the condensate and drains, or secondary condensate regulating system is extraordinarily difficult. Moreover, the priorities of utilizing the individual measures for a quick power regulation are not taken into account. In addition, the control performance has been low since the controlled system is generally nonlinear.